1. Field of the Invention
This invention paticularly relates to the storage and dispensing of diary creamers and other perishable items involving the use of thermoelectric cooling modules.
2. Description of the Prior Art
Portable refrigerators driven by thermoelectric modules is known.Thermoelectric modules typically consist of an array of "couples" composed of alternating P-type and N-type semiconductive material which is primarily Bismuth Telluride. These couples are typically connected in series electrically and in parallel thermally. Upon passage of direct electrical current through the thermoelectric module, heat is pumped from the cold junction to the hot junction at a rate proportional to the direct current applied. Such modules are well known in the art although their usage in the field has been generally limited to situations where compactness, quietness, environmental considerations and overall reliability are particularly important. The aerospace, military and scientific community find application of thermoelectrics. Commercially, however, thermoelectrics is also starting to find growth. Such uses of thermoelectrics is found in recreational vehicles,portable picnic coolers, water/beverage coolers and for butter and cream dispensers.
For the sake of understanding,refrigeration equipment are of the "conduction" type or "forced convention" type. In the forced convection mode of operation, a fan is typically employed to augment heat transfer in the refrigerated space. U.S. Pat. No. 4,726,193 is illustrative of a forced convention type cooler in the form of a picnic box. Dual fans are connected in tandem so that the heat exchanger located within the refrigerated space of the picnic box and the relatively warmer heat exchanger located outside of the box operate with a relatively high velocity of air across their surface. The use of moving air across the heat exchanger surface enhances heat transfer to or from the respective heat exchangers as well as providing uniform temperature distribution in the refrigerated space. "Cold" or hot spots are dramatically reduced when employing moving air in the refrigerated space.
U.S. Pat. Nos. 3,232,063 or 3,088,289 are representative of "conduction" type coolers. In these coolers,the cold side of one or a plurality of thermoelectric modules are directly mounted to a metal surface which contacts the food or beverage to be cooled.
In U.S. Pat. No 3,232,063, an insulated and enclosed unit is equipped with metal shelves toward the rear of the unit which holds the items to be cooled. A door is provided to give ready access to the refrigerated items and to keep the ambient air from otherwise entering the cabinet.
U.S. Pat. No. 3,088,289 illustrates a water cooler employing a thermoelectric module in direct contact with a reservoir of water contained in a vessel.